A commonly prescribed antibiotic may prove useful in preventing or treating depression and other related mood disorders, new research has found.
Doxycycline, an oft-prescribed antibiotic, is used to treat the skin conditions of acne, rosacea and dermatitis, as well as infections of the chest, sinus, eye and pelvis, and is often used as a preventative measure against malaria in certain countries.
Recent research conducted by British and Swiss scientists has found the medication can disrupt the formation of negative thoughts and fears in the brain, and may prove useful in treating or preventing post-traumatic stress disorder (PTSD).
PTSD is caused by an overactive fear memory and includes a broad range of psychological symptoms that can develop after someone goes through a traumatic event.
In a trial involving 76 healthy volunteers who were given either the drug or a placebo dummy pill, those who were on doxycycline had a 60 percent lower fear response than those who were not.
Scientists said the antibiotic works because it blocks certain proteins outside nerve cells, called matrix enzymes, which our brains need to form memories.
Dominik Back, co-leader of the research team and professor at University College London and the University of Zurich, said they had "demonstrated a proof-of-principle for an entirely new treatment for PTSD".
Mr Bach said they want to further explore doxycycline's potential effects, including a phenomenon called "reconsolidation" of fear memories - an approach to helping sufferers of PTSD - where memories and associations can be transformed after an event when the patient experiences or imagines similar situations.